Switch pusher actuator with movable cam plate

ABSTRACT

A switching device, for example, of a type which can be used to actuate a pusher of an electrical switch comprises a mounting base defining a first guide way with a T-shaped guide cam member movable backwardly and forwardly along the first guide way. The cam member carries a generally heart-shaped cam groove which defines a guide cam and it has a sidewall on each side which defines an engagement surface. A compression spring is contained within a blind bore on each side of the guide cam member extending along the guide way and it bears against the stop surface defined at the inner closed end of the bore. The base member includes a second guide way extending at substantially right angles to the first guide way and overlaying the first guide way. A thrust or traction member is movable in the second guide way and it includes a follower in the form of a pin which extends downwardly and into the cam groove. A return spring is connected to the thrust or traction member and it urges it in one direction along its associated second guide way. Movement of the thrust member away from the associated tension spring increases the tension on the spring and it also causes movement of the guide cam member against the compression springs on each side thereof in accordance with the position of the follower in the cam groove.

United States Patent [191 Neuschwander [451 Apr. 30, 1974 A be used toactuatea pusher of an, electrical switch comprises a mounting base defining a first guide way with a T-shaped guide cam member movable back- SWITCH PUSHER ACTUATOR WITH MOVABLE CAM PLATE [75] Inventor: Martin Neuschwander, Spaichingen, wardly and forwardly along the first guide y The Germany cam member carries a generallyheart-shaped cam [73] Assignee: Firma J. & J. Marquardt, Rietheim, groove which defines a guide cam and it has a sidewall Germany on each side which defines anengagement surface. A

. compression spring is contained within a blind bore on [22] Flled' 1973 1 each side of the guide cam member extending along [21] Appl. No.: 348,017 the guide way and it bears against the stop surface defined at the inner closed end of the bore. The base member includes a second guide way extending at 200/153 200/169 substantially right angles to the-first guide way and overlaying the first guide way. A thrust or traction [58] Field of g member is movable in the second guide way and it includes a follower in the form of a pin which extends downwardly and into the cam groove. A return spring [56] References Cited is connected to the thrust of traction member and it UNITED STATES PATENTS urges it in one direction along its associated second 3,704,353 11/1972 Halla 200/1531 guide way. Movement of the thrust member away 3,375,340 3/1968 Wright J from the assqciated tension increases the ten- 3'566'705 3/197" Frydlnan'm 200/153 1 sion'on the spring and it also causes movementof the 3,187,602 6/1965 Cousins 74/1 10 Primary Examiner-Robert K. Schaefer Assistant Examiner-Gerald P. Tolin guide cam member against the compression springs on each side thereof iniaccordance with the position of the follower in the cam groove.

Attorney, Agent, or FirmMcGlew and Tuttle A switching device, for example, of a type which can ABSTRACT 8 Claims, 2 Drawing Figures SWITCH PUSHER ACTUATOR WITH MOVABLE CAM PLATE BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to switching devices and, in particular, to a new and useful switching device which is capable of being used to actuate a member which must be moved in a timed and controlled sequence such as a pusher of an electrical switch.

2. Description of the Prior Art The invention concerns a switching arrangement, particularly with a return spring and with a displaceably mounted and guided member, for example a heartshaped guide cam for a guide pin etc., engaging the latter where the sliding element is arranged between two compression springs and can be displaced against the force of one of them. Due to the selected shape of the guide cam and the arrangement and method of operation of the two springs, the guide pin assumes as a rule two defined positions in the guide cam. Both the sliding element and the switch part carrying the guide pin, etc., have then two defined positions. The reversal is normally started by a pusher. At the first push and subsequent release, the guide pin passes through one half of the guide cam and remains in the first switching position. By pushing again, the guide pin is released and during the release the return spring moves the deflected parts back into their starting position. Naturally a traction member instead of a pusher may be used. The two above mentioned stable displacement positions of the moving elements are used to retain one or several contact arms or bridges in two defined end positions. A least one of them forms a switching position of the respective switch.

The proper passage through the guide cam is only ensured for the guide pin or follower, if it is exactly correlated with this cam in the starting position and neither it nor the part carrying the guide cam is canted or otherwise staggered. In a known switching arrangement of this type, the pusher is held in its starting position by two springs acting from opposite sides. For adjustment in displacement direction, one of these springs can be tightened by means of a screw so that the pusher yields toward the other spring. This type of regulation is very time consuming, however, and depends on the skill and reliability of the worker performing this operation. Beyond that this manual work represents a considerable cost factor in the manufacture of the switching arrangement and of the entire switch containing this switching arrangement.

SUMMARY OF THE INVENTION The present invention provides a switching arrangement of the above mentioned type which ensures a defined position of the parts moving relative to each other despite the elimination of the above mentioned adjustment. The invention includes a switching arrangement which is characterized in that at least one of the ends of the compression springs pointing toward each other bears in the starting position on a stationary stop and that, with only one stop, the force of the spring bearing thereon is equal to or greater than that of the other spring not bearing on a stop. With equal compression springs prestressed in the starting position of the switching cycle, the sliding element assumes a displacement position determined exclusively by the spring force equilibrium. This is the case even if the pressure in the starting position tends toward zero. But if the pressures of the two springs differ in the starting position of the switching cycle, an exact starting position of the sliding element is achieved, since the weaker spring cannot start the stronger one from its stop. The sliding element is clamped between the two springs and assumes a stable starting position, though the two springs exert a different pressure. The differential pressure cannot manifest itself through the stop for the stronger spring. This stop determines the exactly defined starting position and the correlation of the guide cam to the guide pin and depends with a given position of the guide pin, exclusively on the exact fastening of the guide cam on the side of the sliding element facing the stop. Adjustments are thus not necessary, neither with equally nor with differently dimensioned compression springs.

A variant of the invention is characterized in that the two ends of the compression springs pointing toward each other bear in the starting position on a stationary stop, and that the stops are arranged at a distance from each other which corresponds to the extension of the sliding elements in a displacement direction. In this case neither the strength of the two compression springs nor the arrangement of a stronger compression spring to the left or right of the sliding element is of importance for the exact correlation of the guide cam to the guide pin. Determinant are rather only the distances of the two supporting surfaces for the inner ends of the compression springs, as well as the length of the parts of the sliding elements between the distances. The length tolerances to be maintained are easy to control, so that the sliding element can be readily retained in the starting position free from play or substantially free from play. The conditions can be so selected that the springs bear simultaneously on their inner stops and on the associated surface of the sliding element. In this case it is absolutely irrelevant whether the pressure of the individual springs are equal or different, since they cannot act in the starting position. The same holds true if the sliding element bears with play between the stops. A prerequisite for a satisfactory operation is naturally a good support of all moving parts, hence also of the switch element carrying the guide pin etc.

A preferred embodiment of the switching arrangement according to the invention with spiral compression springs is characterized in that the compression springs are arranged each in a blind bore extending substantially parallel to the longitudinal guide of the sliding element, the inner bore ends forming a stop for the respective spring being provided each with an opening for the surface of the sliding element or a part connected with it bearing on the spring ends. The outer ends of the blind bores are preferably closed with a plug or a plate which absorbs at the same time the pressure of the spring. The area of the above mentioned opening" is naturally smaller than the cross sectional area of the blind bore. The differential cross section serves as a supporting surface for the compression spring. The sliding element or a part connected with it enters at first one, and in the course of the second switching operation, the other blind bore during the passage of the guide pin through the guide cam. The respective inner spring end is displaced to the outside so that the spring is tightened.

Another advantageous embodiment of the switching arrangement according to the invention with a plateshaped sliding element is characterized in that the latter is mounted in a guide adapted to the cross section of the plate, and that the blindbores, whose diameter exceeds thethickness of the sliding element, are arranged symmetrically to the center plane of the guide. They need not necessarily be arranged in the in the longitudinal center plane of the guide, they can rather be displaced toward one or the other side of the longitudinal guide. Nor is it absolutely necessary that the longitudinal axes'of the blind bores and of the sliding guide are completely parallel, though this is desirable.

Another feature of the invention is characterized in that the guide embraces the sliding element on all sides and has a slot for the passage of the guide pin whose width corresponds approximately to the thickness of the guide and whose length corresponds to the displacement path of the pin. According to another feature of the invention, the two compression springs can be of-different strength so that the necessary switching forces of the two switching phases are of different size. An expedient further development is characterized in that at least one of the compression springs is connected to a tensioning device in order to be able to adjust and/or vary the actuating forces.

The guide pin is preferably secured on a thrust and/or traction member moving transversely, particularly perpendicularly to the sliding element. It runs in a corresponding guide and is secured against detachment. The thrust member can be connected to a pusher of a switch or be designed as a part thereof, on the other hand, it is also possible to connect a fraction member of the switch to the sliding element. The return spring acts preferably on the member carrying the guide pin and is designed particularly as a spiral compression spring.

Accordingly it is an object of the invention to provide a switching device which comprises a first member defining a guide way in which a guide cam member having a heart-shaped cam groove is movable and which is engaged on respective stop side surfaces by compression springs acting inwardly from respective opposite sides and which is adapted to cooperate with a thrust or traction movement member which is movable in a second guide way at right angles to the first and which carries a follower in the form of a pin which engages in the groove of the cam, and wherein the thrust member is advantageously biased in one direction by a connecting tension spring.

A further object of the invention is to provide a switching device which is simple in design, rugged in construction and economical to manufacture.

For an understanding of the principles of the invention, reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a top plan view of a schematic representation of a switching arrangement constructed in accordance with the invention and with the thrust-traction movement member being omitted for clarity sake; and

FIG. 2 is a section taken along the line IIII of FIG.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in particular, the invention embodied therein comprises'a guide cam member or T-shaped element 1 which is of constant thickness and which is movable backwardly and forwardly in a longitudinal guide way 2 of rectangular cross section which is defined in a base plate 10. The guide cam member 1 is movable along the guide way 2 in the directions of the double arrow 3.

In accordance with the invention, the guide cam member 1 carries a heart-shaped cam groove which defines a guide cam 4 which is engaged by a guide pin 6 which is connected rigidly to a thrust and/or traction member or movement member 5. The movement member 5 can be moved backwardly and forwardly in a guide 7 which extends transversely to the guide way 2 and in the embodiment indicated extends perpendicular to the guide way 2. The movable member 5 may be constructed with a dovetail side edge in order to provide for engagement in the cross guide 7. The movable member 5 is movable in the direction of the arrow 13 shown in FIG. 2 against the force of a return spring 8 which is connected at one end to a pin 1 1 carried by the movable member 5 and is engaged at its opposite end on a bolt 9 which is secured to the base plate 10. The base plate 10 has a slot 12 for the passage of the guide pin 6 which is of a width which corresponds to the thickness of the guide pin.

Inaccordance with a feature of the invention, the base plate 10 includes bores of circular cross section 14 and 15 which receive respective compression springs 16 and 17 which are of substantially the same diameter. The bores 14 and 15 are separated centrally so that their inner blind ends 18 and 19 are spaced apart by an amount corresponding to the width of the guide cam member 1. The bores 14 and 15 intersect the guide way 2 for the guide cam member 1, but the blind ends 18 and 19 form stops which coincide with the side edges of the guide cam member when it is in a neutral position. The guide cam member 1, however, can be moved either to the left or to the right in order to compress the associated springs 16 and 17 only when the guide cam member 1 is moved beyond the inner ends of the blind bores at the locations 18 and 19. For example, upon movement of the slide member to the left in the drawing as indicated, the compression spring 16 would be compressed and pressed against its associated supporting plate 20 when the guide cam member 1 is moved backwardly so that its trailing edge moves beyond the blind bore end 18, the spring 16 becomes fully expanded. A similar movement may be carried out to the right to compress the spring 17. Each spring 16 and 17 may also be inserted into its blind bore with an initial stress but this stress does not act directly on the guide cam member 1. By such an arrangement, the starting position of the guide cam member -1 is therefore, more accurately defined and it falls at the termination of the ends of the blind bore ends 18 and 19. By such a procedure the end or neutral position of the guide cam member 1 is very accurately determined and without requiring any adjustments. The same is also true in respect to the follower or guide pin 6 which can be placed with great accuracy onto the thrust and/or traction member 5. This results in an accurate correlation of the guide pin 6 and the guide cam 4 and ensures thus satisfactoryoperation of the switching arrangement according to the invention.

If the lower end of the thrust and/or traction member 5, which can be provided with a fastening bore 22, for example, is pulled down in the direction of the arrow 13 or if a pressure is exerted on its upper end which is connected to the spring 8 in the same direction, the guide'pin 6 will slide in the direction of the arrow 23 along the leg portion 24 of the heart-shaped guide cam 4 and moved downwardly. The sliding guide cam member 1 will yield to the right and compress the spring 17. As soon as the guide pin 6 has reached the bottom end of the leg 24, it will jump toward the edge 25 of the cutout portion 26 of the cam 4. If the thrust and/or traction member 5 is then released, it is moved upwardly again by the force of the return spring 18. At the same time the force of the compression spring 17 acts on the guide cam member 1 and urges the member 1 in the direction of its starting position. The guide pin 6 will then jump in the direction of rotation through the cut and will stop at the stop edge 27. If no external forces act on the system, a stable end position is thus ensured.

When the thrust and/or traction member 5 is pressed down again in the direction of the arrow 13, starting from the last position of the guide pin 6, the residual force of the compression spring 17 which is still acting on the sliding element 1, will manifest itself as soon as the guide pin 6 has completely released the stop edge 27. The sliding element 1 then jumps to the left until it has reached its starting position and/or the guide pin 6 bears on the outer edge 28 of the bottom end of the right leg 29 of the heart-shaped guide cam 4. A return movement of the member 5 in the direction of the arrow 30 started for example by the return spring 8, moves the guide pin 6 to the inner edge 31 of the second leg 29 of the guide cam on which it then slides upwardly. The guide cam member 1 in FIG. 1 yields to the left and tightens the compression spring 18. As soon as the guide pin has reached the upper end of the right leg 29, the tight spring 18 presses the sliding element 1 again into the center or starting position. The guide pin 6 returns thus into its starting position.

The movement member 5 can be connected, for example, to the pusher of a switch to be molded thereon. This pusher thus assumes a lower position when it is actuated once, but jumps automatically into its upper end position when it is pushed again. These two stable positions can be associated with switching positions of a switch belonging to the pusher. The two springs 16 and 17 need not necessarily have the same strength, rather one can be stronger than the other in order to achieve special effects during the switching operation.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A switching device comprising a housing plate having first means defining a first guide way, a guide cam member having a generally heart-shaped cam groove defining a guide-cam and having an engageable side face on each side and being movable backwardly and forwardly in said first guide way, a compression spring arranged on each side of said guide cam member each having its one end fixed and its opposite end extending toward said guide cam member engagement surface on each side thereof, a stop located in alignment with the side edge engagement surface of said guide cam member when the said guide cam member is located between said compression springs in an intermediate starting position, said springs bearing against said stops in the starting position, said guide cam member being movable beyond said stops in either direction to compress the associated spring on the respective. sides thereof, and a movement member having a follower engaged in the cam groove and return spring means connected to said movement member to move said movement member in a return direction.

2. A switching device, according to claim 1, wherein said base housing includes a circular blind bore for said compression springs extending inwardly from respective opposite sides of said base member, the blind ends of said bores defining said stops and being spaced apart by an amount substantially equal to the width of said guide cam member extending therebetween.

3. A switching device, according to claim 1, wherein said first guide way comprises a rectangular slot extending through said base housing member, said housing member having a blind bore extending inwardly from each side on respective sides of said guide cam member of a diameter larger than the thickness of said rectangular guide way so as to extend it beyond the top and bottom of the guide way, the inner closed ends of said bores defining stops for said compression springs, said guide cam member being movable through the bores to compress the associated springs therein.

4. A switching device, according to claim 1, wherein said guide way embraces said guidecam member on all of its sides, said base housing member having an opening therethrough for the passage of the guide pin having a width corresponding essentially to the thickness of said guide pin and having a length corresponding to the displacement path of said pin and including second means defining a second guide way at substantially right angles to said first guide way, said movement member being movable in said second guide way.

5. A switching device, according to claim 1, wherein said compression springs are of different strength.

6. A switching device, according to claim 1, wherein one of said compression springs is connected to a tensioning device.

7. A switching device, according to claim 1, including a second means in said base plate defining a second guide way at substantially right angles to said first guide way, said movement member being movable in said second guide way and having said follower engaged with said cam groove, said return spring being connected to said movement member to bias it in one direction along its associated guide.

8. A switching device, according to claim 7, wherein said movement member may be displaced against the force of its return spring.

v UNITED- STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. I 5,808, 388 v Dated April 50, 197 1- lnventol-(s') Martin Neuschwander- It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the title page, the following should be. added:-

- Foreign Application Priority Data April 19, 1972- Germany -P22 .188 +8.3

Signed and sealed this 10th" day v of December 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PC4050 (10-69) 1 I I USCOMM-DC 60376-P69 I I U.5. GOVERNMENT 'IINTING OFFICE: 

1. A switching device comprising a housing plate having first means defining a first guide way, a guide cam member having a generally heart-shaped cam groove defining a guide cam and having an engageable side face on each side and being movable backwardly and forwardly in said first guide way, a compression spring arranged on each side of said guide cam member each having its one end fixed and its opposite end extending toward said guide cam member engagement surface on each side thereof, a stop located in alignment with the side edge engagement surface of said guide cam member when the said guide cam member is located between said compression springs in an intermediate starting position, said springs bearing against said stops in the starting position, said guide cam member being movable beyond said stops in either direction to compress the associated spring on the respective sides thereof, and a movement member having a follower engaged in the cam groove and return spring means connected to said movement member to move said movement member in a return direction.
 2. A switching device, according to claim 1, wherein said base housing includes a circular blind bore for said compression springs extending inwardly from respective opposite sides of said base member, the blind ends of said bores defining said stops and being spaced apart by an amount substantially equal to the width of said guide cam member extending therebetween.
 3. A switching device, according to claim 1, wherein said first guide way cOmprises a rectangular slot extending through said base housing member, said housing member having a blind bore extending inwardly from each side on respective sides of said guide cam member of a diameter larger than the thickness of said rectangular guide way so as to extend it beyond the top and bottom of the guide way, the inner closed ends of said bores defining stops for said compression springs, said guide cam member being movable through the bores to compress the associated springs therein.
 4. A switching device, according to claim 1, wherein said guide way embraces said guide cam member on all of its sides, said base housing member having an opening therethrough for the passage of the guide pin having a width corresponding essentially to the thickness of said guide pin and having a length corresponding to the displacement path of said pin and including second means defining a second guide way at substantially right angles to said first guide way, said movement member being movable in said second guide way.
 5. A switching device, according to claim 1, wherein said compression springs are of different strength.
 6. A switching device, according to claim 1, wherein one of said compression springs is connected to a tensioning device.
 7. A switching device, according to claim 1, including a second means in said base plate defining a second guide way at substantially right angles to said first guide way, said movement member being movable in said second guide way and having said follower engaged with said cam groove, said return spring being connected to said movement member to bias it in one direction along its associated guide.
 8. A switching device, according to claim 7, wherein said movement member may be displaced against the force of its return spring. 